68640928 has 24 divisors (see below), whose sum is σ = 136406592. Its totient is φ = 33998016.

The previous prime is 68640919. The next prime is 68640931. The reversal of 68640928 is 82904686.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6600 + ... + 13447.

It is an arithmetic number, because the mean of its divisors is an integer number (5683608).

Almost surely, 2^68640928 is an apocalyptic number.

It is an amenable number.

68640928 is a deficient number, since it is larger than the sum of its proper divisors (67765664).

68640928 is a wasteful number, since it uses less digits than its factorization.

68640928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20164 (or 20156 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 68640928 is about 8284.9820760216. The cubic root of 68640928 is about 409.4438781838.

It can be divided in two parts, 686 and 40928, that added together give a palindrome (41614).

The spelling of 68640928 in words is "sixty-eight million, six hundred forty thousand, nine hundred twenty-eight".